Knitting of tubular articles on circular knitting machines



KNITTING OF TUBULAR ARTICLES 0N CIRCULAR KNITTING MACHINES Filed Oct.14, 1965 3 Sheets-Sheet 1 FIGJ. I

IA/VEx/fo e FOL/ u ees/e 0y R. PEBERDY 3,402,575

' Sept. 24, 1968 KNITTING OF TUBULAR ARTICLES ON CIRCULAR KNITTINGMACHINES Filed Oct. 14, 1965 3 Sheets-Sheet 2 5 v a 2 a a 6 m B Y .3 v F9 r///// /AA,A 2 n llllll. llbll. llll l8 -2, A w w a A? k w v t a &

Im/EA/foe Tenn/0 105851919X yea- Sept. 24, 1968 KNITTING OF TUBULARARTICLES 0N CIRCULAR'KNITTING MACHINES Filed Oct. 14, 1965 v 3Sheets-Sheet 5 INvENToR R01. ND ?'8ERJ United States Patent 3,402,575KNITTING 0F TUBULAR ARTICLES 0N CIRCULAR KNITTING MACHINES RolandPeberdy, Leicester, England, assignor to The Bentley Engineering CompanyLimited, Leicester, England, a British company Filed Oct. 14, 1965, Ser.No. 496,007 Claims priority, application Great Britain, Oct. 16, 1964,42,246/64 Claims. (Cl. 66-107) ABSTRACT OF THE DISCLOSURE A procedureand means for knitting a succession of tubular articles on a circularknitting machine by which each article is pressed off from the needleson its completion and a fresh course to start a succeeding article iscommenced during the pressing off of a preceding article while a portionof yarn temporarily joins the articles, such joining portion of yarnbeing severed before pressing off of the preceding article has beencompleted. The means provided operates needle actuating cam means forthe pressing off of each article and feeds yarn extending fom the end ofa complete article into the hooks of the needles from which thepreceding article has been pressed off, and also operates to sever theyarn in a length thereof extending across a small group of needlesbetween the substantially completed and newly commenced articles.

This invention is for improvements in or relating to the knitting oftubular articles on circular knitting machines and is concerned moreparticularly with the production of knitted articles of footwear. Theinvention has for an object to provide a simple and effective procedurefor the production of a succession of knitted tubular articles. Theinvention may be applied conveniently to use with circular rib knittingmachines and especially to machines of the opposed co-axial needlecylinder type.

In the production of mens socks it has been the practice for many yearsto knit the sock blanks in continuous succession in string formationjoined end to end. After the production of a string of sock blanks theindividual blanks are separated by hand either by cutting or by removalof a draw thread and afterwards closed at the toe end. The separation isa time consuming operation and proposals have been made to provide aprocedure whereby the socks can be separated automatically. In theproposals so far made certain disadvantages are involved either byimpairing the quality of the product or by introducing difficulties inprocedure or introduction of an additional operation. The inventionseeks to provide a procedure wherein such disadvantages are largely orwholly avoided.

In accordance with the invention there is provided a method of knittinga succession of tubular articles on a circular knitting machineaccording to which each article on completion is pressed off from theneedles and, before its pressing off is completed the setting up of afresh course is commenced to start the next succeeding article with theyarn temporarily connecting the articles together, and during thepressing off of the preceding article the yarn joining it to thesucceeding article is severed to separate the articles from one another.Thus a very simple procedure is provided whereby a succession of tubulararticles is knitted each being automatically separated immediately afterits completion from the succeeding article.

An important advantage of the improved procedure is that the yarn feedercan be maintained in feeding position during transition from theknitting of one article to the knitting of the next, thereby avoidingthe need to take any special steps to cause the free yarn end to betaken by needles which are devoid of stitches. The yarn held by the lastneedle to knit a preceding article is laid across the stems of a groupof needles immediately beyond the last needles holding loops of thepreceding article and the severing takes place in a short length of yarnlaid across such needle stems. The severing of the yarn takes placeafter the yarn has been taken into the hooks of the needles succeedingsaid group and whilst the short length of yarn laid across the needlestem is held between the needles succeeding said group and those stillholding loops of the preceding article. Such severing takes place afterthe initial course of the succeeding article has been commenced bymovement of needles into the hooks of which the yarn has been laid.

In practising the invention the severing of the yarn between succeedingarticles may be etfected by subjecting the yarn to local strain tofracture it. Such fracture may be brought about by diverting a portionof the yarn to elongate its path and thereby set up the bursting strainwhich diversion may be brought about by a sinker movement.

The invention also comprises a circular knitting machine organised toknit a succession of tubular articles and having means arranged to pressoff each article as soon as it is completed, means for feeding the yarnextending from the end of a completed article into the hooks of needlesfrom which the fabric has been pressed off to commence setting up of anew course before the preceding article has been fully pressed off theneedles, and means whereby after the preceding article has beencompleted and the new course started the yarn extending from thepreceding article to the succeeding article is severed to separate thearticles. The yarn severing means may consist of means for subjectingthe yarn t0 localised strain to burst it.

The yarn severing means conveniently comprises means for operatingsinkers at appropriate times to engage yarn between the appropriatearticle and the next succeeding article and cause the yarn to besevered.

A convenient procedure for practising the improved method and animproved machine constructed and operating in accordance with theinvention will now be described by way of example with reference to theaccompanying drawings in which:

FIGURE 1 is an elevation view of a circular knitting machine to whichthe invention is applied:

FIGURE 2 is an enlarged detail elevation view in central cross-sectionof portions of the needle cylinders of the machine showing an articleabout to be pressed off and the commencement of knitting a succeedingarticle, and

FIGURE 3 is a developed view of a cam lay-out employed in the cam systemof the machine being a machine having two yarn feeding stations.

The invention is illustrated in the drawings as being applied to anopposed needle cylinder circular knitting machine suitable for knittingmens socks and organised for transfer of double ended needles from onecylinder to the other in a manner well known to those skilled in the artfor the purpose of changing between plain knitting and rib knitting asand when required.

It is to be understood, however, that the invention is also applicableto a machine having only a single needle cylinder as used for knittingplain fabric for example a machine organised for knitting ladiesstockings or one organised for knitting other plain tubular fabric.

Referring to FIG. 1 the circular knitting machine therein shown is ofgenerally orthodox form comprising a supporting frame 10, bed plate 11,lower and upper needle cylinders 12 and 13, and a main control drum 14.Lower and upper cam boxes and 16 are also shown, and the operation ofmovable instrumentalities used in controlling operation of the machine,such as bolt cams and yarn feeders, is effected by control rods banks ofwhich are indicated at 17 and 18. The machine also has supportingmountings 19 for yarn supply packages and brackets 20 and 21 carryingmountings 22 and 23 for yarn guiding and tensioning means.

The circularly knitted tubular articles, in this case mens socks, aredelivered downwardly through the bottom cylinder 12 into a dischargetube 24 through which they are drawn by air flow or suction to adelivery cup 25 from which they are discharged at appropriate times intoa removable bucket-like container 26.

Further details of the machine can be seen from FIG. 2 which shows acentral section through adjoining parts of the needle cylinders 12 and13, certain orthodox parts of the machine being shown diagrammaticallyin block outline form so that parts relevant to the invention can beseen more clearly. Thus the cylinder 12 is shown equipped with bottomcylinder sliders 27 carrying double ended needles 28 and within theupper end of bottom cylinder 12 there is a sinker ring 29 carryinginside sinkers 30 having butts 31 controlled by sinker cams 32, 33. Atubular knitted article practically complete and partly pressed off fromthe needles is shown at 34 and it has loops of its final course stillheld on needles of the bottom cylinder indicated at 28a in FIG. 2 and onother needles to the right thereof the heads of which are below the topof the sinker ring 29 and therefore not seen. The fabric still engagedwith on these lowered needles is indicated at 35. To the right of thefabric 35 as seen in FIG. 2 there are seven raised needles the heads ofwhich are indicated at 2817, these being the first needles from whichloops of the article 34 were pressed off.

The socks 34 are normally knitted from the top or welt end to the toeusing both the main and back feeds where appropriate and the procedurefollowing the completion of each sock blank will now be described withreference to the cam layout shown in FIG. 3.

Following knitting of the toe pouch of the blank 34 by the normalprocedure of reciprocatory knitting, complete circular courses of plainfabric are knitted at the main feed to provide in known mannerunravelling courses which will afterwards be removed following closingof the toe end as by linking. On reaching the point where the next sockis to commence the back feed bolt cam shown at 101 (FIG. 3) isintroduced to engage a small group of medium butt sliders 27 (being inthe example shown the seven carrying the needles 28b) which are situatedin the middle of the short knitting butts in the bottom cylinder. Theknitting butts of the boom sliders 27 are arranged in conventionalmanner, i.e., short butts in the heel half and long butts in the instephalf. As the group of medium butt sliders 27 pass down the bolt cam 101the cam moves right in so that all following sliders will be lowered. Itremains in for one cylinder revolution only and as no yarn is being fedat the back feed, the needles will all be pressed off as their slidersengage this cam. Continuing from the stage where the group of mediumbutt sliders have passed down the cam 101 they now proceed below cam 102until their transfer butts encounter cam 103. They are then lifted bythis cam so that their knitting butts ride up cam 104 and raise theirneedles to clearing height. As there is no yarn on these needles at thisstage it is necessary to open the latches by other means and in thisexample the upper cylinder sliders indicated at 36 in FIG. 3 aredirected to a level where their noses shown at 105 (which are formedwith chisel ends suitably shaped'for the purpose) encounter the needleswhose sliders are progressing up the cam 104 and, by engagement of theirchisel ends between the latches and hooks of the needles, open theirlatches.

The empty needles, led by the group 2811 whose sliders have medium buttscontinue at clearing height until they meet the needle lifter bolt cam106 which is set to lift the medium butt group of sliders to a heightabove clearing height (being the height to which they are raised duringthe knitting of a heel pouch) while allowing the short butts to pass byit. The cam 106 is subsequently drawn right out to allow the long buttsto pass by also at clearing height.

The state of affairs at this stage is as follows. Knitting of the finalcourse of the finished sock is taking place at the main feed point Awith sliders passing down the stitch cam 107. The sliders are thenraised through the engagement of their transfer butts with cam 108 toraise the needles to clearing height as shown at (and at 28a in FIG. 2).Needles are being pressed-off at cam 101 (as the needles to the left ofgroup 28a move fully downwards) and latches of empty needles are beingopened as sliders are being raised by cam 104. Empty needles areapproaching the main feed point A at clearing height led by the group ofseven or so needles (whose sliders have medium knitting butts) at heelheight.

As the group of needles at heel height (28b in FIG. 2) pass by the mainfeed point A the yarn is laid by the feeder (shown at 37 in FIG. 2) fromthe last needle to knit prior to this group outside the stems of thegroup 28b at heel height and into the hooks of the following emptyneedles. The stretch of yarn laid outside the stems of the group ofseven or so needles at heel height is a more or less straight length ofyarn being indicated at 38 in FIG. 2, and it is laid against the needlesstems while the sinkers are out at the main feed point A. The sinkersare thrown out, as normally, approximately between the points X -X inFIG. 3. When the stretch of yarn just referred to reaches the point Xand the sinkers move in to perform their normal knocking-over function,they will take the yarn 38 in between the needle stems. As the stretchof yarn is not nearly long enough to assume this sinuous form it breaksby the time three or four sinkers have moved in to the knock-over point.Now although this is the actual separating point of the two socks theyarn ends are both controlled by the sinkers.

The problem of refeeding the yarn to empty needles after pressing-off anindividual article is completely solved by this method because thefeeder remains in action. The actual releas of the finished sock andcontinued pick-up and knitting of the first course of the new sock willnow be described by continuing the description from the instant ofbreaking the yarn.

The remaining knitted loops of the finished article still suspended fromtheir needles extend between the point of breakage of the yarn and theneedles at 28a pressing off their stitches as they pass down the backfeed bolt cam 101. These remaining needles extend between the points Y-Yin FIG. 3 and as rotation of the needle cylinder continues these needleswill also pass down cam 101 and press-off, thus releasing the finishedarticle to be discharged by air flow through the tube 24.

The needles following the group of seven or so needles 2812 at heelheight (which have the leading end of yarn for the new article trappedbetween their stems and the sinkers) all receive yarn in their hooks atthe main feed point A. These needles had all pressed off earlier at theback feed bolt cam 101 and their latches had been opened as previouslydescribed so that they are ready to receive the yarn at the main feedpoint A. The butts of the group 28b at heel height pass above the backfeed bolt cam 101 and the following needles after receiving the yarn arelowered by their butts passing down stitch cam 107 and are allowed toremain low, upthrow cam 108 being withdrawn, so that they do not cleartheir loops and are caused to pass the back feed station in this lowposition. The sinkers re-engage the yarn before the needles are raisedagain. Alternate needles are raised toclearing height by means of theirpattern jacks lifting them so that their sliders pass up cam 104 andthese alternate needles are then transferred by the patterning mechanism(not shown) to the top cylinder. The needles thus arrive at the mainfeed point A in a 1/1 set-out, i.e., alternate needles in the topcylinder and intermediate needles in the bottom cylinder with the yarnfollowing a Zig-zig path from the hooks of the intermediate (bottomcylinder) needles to the alternate (top cylinder) needles where it isheld behind their own latches. At the main feed point A the respectiveslider butts of these needles follow tracks 109 and 110. It should beremembered that there are no actual knitted loops on these needles asthey enter the main feed station A, and the yarn merely lies in azig-zag path from needle to needle.

As the needles pass through the feeding station the sliders of the ribneedles follow track 110 and are raised by stitch cam 111. Althoughthere is only one yarn on the needles and no stitch yet, a good feed isensured because the yarn lies in the hooks of the plain needles whosesliders are in track 109 and behind the latches of the rib needles whichare held open by the latchguard and the rib latches are closed by thisyarn on to the new yarn. Knitting takes place on rib needles only. Therib clearing bolt 112 is withdrawn so that the newly formed rib loopsare not cleared at this point but are kept at a high level to retain theloops on the needles as they pass the back feed point. The plain needlesremain low at the back feed (cam 108 being withdrawn) and the ribdepressor 113 at the back feed lowers the rib loops so that the sinkersmove in over the yarn. The plain needles are then all raised up theclearing cam 104 and their sliders follow track 114 to cause them toknit at the main feed A.

If a welt is required (and it is not necessary to have one with thismake-up) the welt bolt is withdrawn at this point so that the formationof the welt starts immediately.

If it is desired to incorporate an elastic yarn in the top of the sockit may be introduced to a few needles knitting 1/1 rib just before thestart of the welt. The elastic yarn is actually fed to the needle of thefirst slider following the aforementioned group of seven or so mediumbutt sliders carrying the needles 28b in the middle of the shortknitting butts.

The group of sliders 36 in the top cylinder immediately above this grouphave long butts to allow the welt bolt to be withdrawn at thecommencement of the welt. By extending this group of long butts a fewneedles further than the group of medium butts in the bottom cylinderthese few needles will knit 1/1 at the main feed to lock the start ofthe elastic yarn and will then enter the welt track a course later thannormal.

It should be emphasized that the needle selection for the make-upcourses desc-ribed in carrying out this invention is given by way ofexample only. The method of parting the yarn du-ring the process ofknitting, to divide the articles, may be used with other methods ofcommencing articles and is not in any way restricted by the examplegiven.

What I claim is:

1. A method of knitting a succession of tubular articles on a circularknitting machine comprising the steps of (a) pressing off from theneedles each article on its completion, (b) commencing setting up afresh course to start a succeeding article during pressing off of thepreceding article, with a portion of yarn temporarily joining thecompleted and newly commenced articles, and (c) severing the joiningyarn before the pressing off of the preceding article has beencompleted.

2. A method according to claim 1 wherein the severing of the joiningyarn between successive articles occurs in a short length of yarn laidacross the stems of a group of needles immediately beyond the lastneedles holding loops of the preceding article.

3. A method according to claim 2 wherein the severing of the joiningyarn takes place after the yarn has been taken into the hooks of needlessucceeding the group across the stems of which the joining yarn is laidand whilst the joining yarn is held between the needles into the hooksof which it has been taken and those needles still holding loops of thepreceding article.

4. A method according to claim 1 in which the severing of the yarnbetween succeeding articles is effected by subjecting the yarn to localstrain to fracture it.

5. A method according to claim 4 wherein the localised strain forfracturing the yarn is produced by causing at the appropriate timeelongation of the path of the yarn.

6. A circular knitting machine organised to knit a succession of tubulararticles and having in combination with a needle cylinder equipped withneedles and cam means for operating said needles, means to operate saidcam means so as to press off each article from the needles as it iscompleted, means for feeding ya-rn extending from the end of a completedarticle into the hooks of the needles from which the preceding articlehas been pressed off to commence setting up fabric for a new articlebefore the preceding article has been fully pressed off from theneedles, and means for severing the yarn extending between the precedingarticle and the newly commenced article before the preceding article hasbeen fully pressed off from the needles.

7. In a circular knitting machine organised to knit a succession oftubular articles, the combination comprising a needle cylinder, needlesin said cylinder, cam means for operating said needles, yarn feedingmeans organised to feed yarn to the needles and to continue such feed ofthe yarn from a preceding article to a succeeding article, means forpressing off each article from the needles as it is completed, meanseffective on completion of an article and on commencement of asucceeding article to sever the yarn between the articles to separatethem, and additional cam means for raising a small group of needlesfollowing the last ones holding a preceding article so that stems ofsuch raised needles receive a portion of the yarn in readiness forseverance.

8. A combination according to claim 7 comprising a sinker bed, sinkersin said bed and sinker operating means arranged to cause the sinkersco-operating with the small group of needles to engage the portion ofyarn laid across the stems of said needles.

9. A combination according to claim 7 wherein the said additional cammeans comprises a bolt cam to effect raising of the small group ofneedles to receive the portion of yarn between the articles and buttsare associated with said needles for selective engagement by said boltcam.

10. A combination according to claim 7 comprising an inside sinker ringmounted within the needle cylinder, inside sinkers mounted on said ringand sinker cams organised to move sinkers associated with the smallgroup of needles to move them inwardly when said needles are raised toengage with the portion of yarn against the needle stems.

References Cited UNITED STATES PATENTS 1,285,096 11/1918 Fisher 66-1471,691,887 11/1928 Matthews 66-107 2,385,056 9/1945 Bromley et a1. 66-1072,398,785 4/1946 Grothey 66-107 2,498,096 2/1950 Schaefer 66-1473,282,070 11/1966 Perkins 66-147 WM. CARTER REYNOLDS, Primary Examiner.

